(Oregon Coast) – One of the more mysterious delights of the Oregon coast is an unknown little wonder called “magic rocks” on some beaches. On just a handful of spots – and it depends on tidal conditions – you'll hear a surreal rattling noise come from the rocks.

It’s as if the tides momentarily gives them life, as they shimmy, shake and shudder while making an almost chirping sound, like giant Mexican jumping beans that have grown to freakish size and now inhabit the tideline.

You have to have large, rounded cobblestones at the tideline to do it. The water bounces them around and causes them to clatter against each other, but in this rather smile-inducing rush of pops, rattles and clicks that sounds, well, magical.

The term "magic rocks" actually comes from a nickname the locals have given to a beach just south of the Arch Cape Tunnel - one that's almost completely made up of these polished stones, and where the sound is almost continuous. They call it "Magic Rocks Beach,” and it is unusual in other ways as well.

Here the noises in this video:

On the northern edge of Oswald West State Park, right after you emerge from the Arch Cape Tunnel, look for Falcon Cove Road. At the end of this winding, twisting neighborhood road, you'll find this delightfully odd beach. It is a residential district, so you’ll want to be respectful here as you park near a somewhat slippery, muddy beach access.

If the tide isn't touching the rocks it won't happen, but it does a little more than 50 percent of the time.

Most such spots are on the north Oregon coast, and almost none of them do it as much as here at Falcon Cove Road. Newport's Yaquina Head, however, has just such a spot, and it does it almost all the time.

You can't always get close enough, however, because tidal conditions get too dangerous down there.

In Newport, it's called Cobble Beach and it's a long walk down only one stairway. It's of course, even longer coming back up. It's also home to a lot of surreal, huge grains of black sand, adding to the otherworldly feel of the place. (Seen above).

The tiny village of Cape Meares (the neighborhood located just beneath the cape of the same name) also hosts this feature. The town's middle and northern beach accesses are where it happens. During most of winter and at higher tides you'll hear it here. In fact, at Cape Meares it's absolutely the loudest of all the magic rock beaches of the Oregon coast.

There's some interesting geology behind these unique and noisy features.

Tom Horning, a geologist in Seaside, said these stones usually come from nearby headlands. Which is why most magic rock beaches are next to some sort of headland or another.

The sizes of the stones differ from place to place, making different kinds of noises and higher or lower decibels.

“The size of the rock is an indicator of the energy of the water and size availability of the rock in the first place,” Horning said. After they fall from headlands, the tides and currents move them around.

“As the rocks are transported along, they jostle and grind against each other, becoming rounded,” Horning said. “It takes only a few months in the surf to round most rocks. Some rocks come from source areas (cliffs and mountainsides) where fractures are abundant. They start as fractured rock and can fall apart quickly in the surf, forming small rocks. Other rocks begin as large, unfractured stone, so they resist breaking apart to smaller pieces, leaving a deposit of large boulders. Nature takes what is available and makes what is possible.”

Other places you may spot them: Arch Cape near Canon Beach has some of this if the tide is right, as does the southern end of Strawberry Hill, near Yachats.

It's important to keep beach safety in mind here. The tidelines at these spots are especially dangerous if it's happening as you have the added issue of possibly slipping on these rocks and getting sucked into the ocean. Luckily, you can get close to view it and hear from a short – but safe – distance. Oregon Coast Hotels in these areas - Where to eat - Maps - Virtual Tours